815533393920 has 384 divisors, whose sum is σ = 2998593561600. Its totient is φ = 185357500416.

The previous prime is 815533393897. The next prime is 815533393943. The reversal of 815533393920 is 29393335518.

It is an interprime number because it is at equal distance from previous prime (815533393897) and next prime (815533393943).

It is a tau number, because it is divible by the number of its divisors (384).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38481567 + ... + 38502753.

It is an arithmetic number, because the mean of its divisors is an integer number (7808837400).

Almost surely, 2^815533393920 is an apocalyptic number.

815533393920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 815533393920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1499296780800).

815533393920 is an abundant number, since it is smaller than the sum of its proper divisors (2183060167680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

815533393920 is a wasteful number, since it uses less digits than its factorization.

815533393920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21403 (or 21383 counting only the distinct ones).

The product of its (nonzero) digits is 2624400, while the sum is 51.

The spelling of 815533393920 in words is "eight hundred fifteen billion, five hundred thirty-three million, three hundred ninety-three thousand, nine hundred twenty".